Principal Network Engineer (Distributed Networks) in Bristol

We're building the UK's next generation engineering powerhouse, providing critical technology that strengthens national security and resilience. We specialise in turning advances in sensing, AI, and communications into operational capability for the edge, where connectivity may be degraded or denied. Our work focuses on accelerating the deployment of technology, improving decision-making for frontline teams, and protecting people and critical assets in demanding environments. Headquartered in Bristol, Rowden employs around 160 people and operates over 20,000 square feet of engineering and manufacturing facilities. We have a growing international footprint and are one of Europe's fastest-growing engineering businesses.

About the role

We’re looking for a Principal Network Engineer to design and own the distributed networks that connect our systems in environments where most networks fail. You’ll work on mesh networks across moving nodes, multi bearer communications, and software defined overlays that can adapt to outages, degraded links, and interference. You’ll help build zero-trust connectivity between far edge devices and central services in networks where the topology changes and bandwidth is limited. This is difficult networking work. Traffic may need to move across several different bearers, each with different latency, reliability, and cost. Decisions have to be made automatically, in real time, and under changing conditions. We build systems with the assumption that links, nodes, and services will fail. The work is technical, practical, and important. You’ll solve real operational problems for people working in demanding environments where communications matter. You’ll help define the architecture and engineering standards, while staying hands on with design, prototyping, testing, and operational delivery. This role is for an engineer who wants to apply deep networking expertise to hard distributed systems problems and build things that work in the real world. This role offers hybrid working with a minimum of 3 days per week on-site at our Bristol HQ. Candidates must be eligible for SC clearance.

Key areas of responsibility

• Designing and building distributed networks, from device-level networking through overlay fabrics to integration with customer and partner networks.
• Designing mesh, SD-WAN, and overlay topologies that perform reliably in denied, disrupted, intermittent, and limited (DDIL) environments.
• Designing multi-bearer link aggregation, failover, and path-selection mechanisms across LTE, satellite, and bespoke RF links.
• Establishing the zero-trust connectivity model for our systems: certificate-based device identity, mutual authentication, and policy enforcement at the network edge.
• Owning routing, traffic engineering, QoS, and congestion behaviour across constrained and adversarial links.
• Building observability into networks that are by nature partly opaque, including telemetry, path analytics, and operator-facing situational awareness.
• Acting as a key technical decision-maker, balancing trade-offs across resilience, performance, security, and operational simplicity.
• Producing high-quality network architecture documentation, design artefacts, and reference patterns.
• Working directly with users, partners, and stakeholders to make sure the network architecture meets real operational needs.

Key skills, experience and behaviours

We are looking for a principal-level engineer with deep distributed networking expertise and a track record of applying it to genuinely demanding problems.

• Deep, hands-on networking background: routing protocols, L2/L3 networking, NAT, multicast, and the practical realities of running them at the edge.
• Strong experience with overlay and tunnelling technologies such as WireGuard, and IPsec.
• Practical experience with SD-WAN, software-defined networking, or programmable data planes.
• Working knowledge of mesh networking protocols and a feel for where they shine and where they break.
• Strong Linux networking: nftables/iptables, namespaces, tc, eBPF-adjacent tooling, and debugging at the packet level.
• Experience designing zero-trust network architectures, including PKI, certificate lifecycle, and identity-aware policy.
• Strong scripting and automation and infrastructure-as-code for network configuration.
• Proven ability to provide technical leadership and influence engineering direction, operating autonomously in complex and ambiguous environments.
• Excellent communication skills, both written and verbal, with the ability to explain complex networking concepts clearly to a range of stakeholders.

• Direct experience designing, deploying, and supporting networks at the far-edge in denied, disrupted, intermittent, or lossy environments.
• Background in regulated sectors delivering complex connected systems, such as defence, national security, telecommunications, or critical infrastructure.
• Experience with multi-bearer / multi-path systems combining cellular, satellite, Wi-Fi, and bespoke RF links.
• Familiarity with MANET routing (OLSR, BATMAN, OSPF-MDR) or disruption-tolerant networking approaches.
• Familiarity with RF and waveform-level constraints sufficient to design well at the IP layer above them.
• Experience with network observability platforms and telemetry pipelines for distributed networks.

About you

• Systems thinker: You reason naturally about large-scale, interconnected networks and balance short-term delivery with long-term architectural health.
• Hands On: You're excited by building, not by delegating.
• Curious & Adaptive: You continuously learn and you're comfortable working in spaces where the right answer isn't yet known.
• Pragmatic: You pick the right tool and the right level of process for the problem, and you know when an elegant protocol is the wrong choice operationally.
• Problem-solver: You troubleshoot and resolve complex network issues efficiently, including the ones that only show up in the field.
• Continuous improvement mindset: You proactively identify opportunities to improve networks, processes, and ways of working.

Working at Rowden

We are committed to building a flexible, inclusive, and enabling company. Our aim is to create a diverse team of talented people with unique skills, experience, and backgrounds, so please apply and come as you are! We also recognise the importance of flexible working and support this wherever we can. We typically operate a flexible, hybrid-working model, with an average 3 days in the office each week (dependent on the role). We welcome the opportunity to discuss flexibility, part-time working requirements and/or workplace adjustments with all our applicants. Rowden is a Disability Confident Committed company, and we actively encourage people with disabilities and health conditions to apply for our roles. Please let us know your requirements early on so that we can make sure you have everything you need up front to help make the recruitment process and experience as easy as possible. Finally, if you feel that you don’t meet all the criteria included above but have transferable skills and relevant experience, we’d still love to hear from you!